Question

all vertebrates are chordates but then why all chordates are not vertebrates

Answer 1

All vertebrates are chordates but then why all chordates are not vertebrates

Answer => members of subphylum vertrebata possess notochord during the embryonic period and hence thus the notochord is being replaced by a bony vertebral column in adults

Answer 2

Answer:

Vertebrates include amphibians, reptiles, mammals, and birds, as well as the jawless fishes, bony fishes, sharks, and rays. More than 64,000 species of vertebrates have been described, but the extant vertebrate species represent only a small portion of all the vertebrates that have existed.